Novel flame retardants

Abstract

This invention relates to a flame retardant, a plastic composition containing the flame retardant, and a polyphosphate. [Solution] A flame retardant comprising a polyphosphate, wherein the polyphosphate has a cation of at least one 1,3,5-triazine compound, and one of the at least one 1,3,5-triazine compound is melamine, wherein the flame retardant comprises at least one condensation product of melamine.

Description

Technical Field

[0001] The present invention relates to a flame retardant, a plastic composition containing the flame retardant, and a polyphosphate.

Background Art

[0002] To impart flame retardancy to plastics, a number of substances are known, and these substances can be used alone or in combination with further substances that impart similar or synergistic flame retardancy.

[0003] For example, the use of polyphosphates of 1,3,5-triazine compounds for such applications is known from the prior art. These compounds are incorporated into plastics by extrusion, especially into (glass fiber-containing or non-containing) polyamides and polyesters, and are usually processed at high temperatures, i.e., by injection molding.

[0004] As such polyphosphates of 1,3,5-triazine compounds, those having an average degree of condensation (number average) higher than 20 and a molecular ratio of triazine compound to phosphoric acid less than 1.1 are known from Patent Document 1.

[0005] Patent Document 2 describes 1,3,5-triazine derivatives of polyacids containing phosphorus, sulfur, and oxygen, and methods for producing them. The ratio of the 1,3,5-triazine compound to phosphorus in the disclosed triazine polyphosphate derivatives is higher than 1.1.

[0006] Patent Document 3 also describes polyphosphates of 1,3,5-triazine compounds. This salt has a 1,3,5-triazine content of 1.1 to 2.0 moles per mole of phosphorus atom of a triazine compound selected from the group consisting of melamine, melam, melem, melon, ammeline, ammelide, 2-ureidomelamine, acetoguanamine, benzoguanamine, and diaminophenyltriazine.

[0007] These polyphosphates, known from prior art, generally achieve only moderate flame retardancy when incorporated into compositions to be protected. Furthermore, these phosphates tend to leach from the material over time. This not only further reduces the flame retardant effect, but the release also poses health risks, particularly in household applications. Moreover, processing products using extruders, especially at temperatures exceeding 250°C, can cause the flame retardants to decompose or the surface of the extruded material to become rough. This effect is particularly pronounced when flame retardants are incorporated into glass fiber reinforced plastics. Processing becomes especially difficult when additional synergistic flame retardants, such as phosphinate-based products like aluminum diethylphosphinate, are included in addition to the main flame retardant and fillers. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. WO00 / 02869 [Patent Document 2] European Patent No. 0974588 [Patent Document 3] European Patent No. 1095030 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Accordingly, taking this into consideration, an object of the present invention is to provide a polyphosphate-based flame retardant of the above type, preferably halogen-free, environmentally friendly, and especially recyclable, which has flame retardant properties similar to or better than those of flame retardants known in the prior art, and further has a low tendency to leach out, thereby achieving durable and harmless flame retardancy, especially for polymer materials. Furthermore, the present invention aims to ensure unlimited processability of polymer materials containing flame retardants, even in multi-stage processing or at high temperatures. [Means for solving the problem]

[0010] This objective is achieved by the flame retardant described in claim 1. [Modes for carrying out the invention]

[0011] The flame retardant according to the present invention comprises at least one polyphosphate containing a cation of at least one 1,3,5-triazine compound, wherein one of these 1,3,5-triazine compounds is melamine. Therefore, it is a polyphosphate of a 1,3,5-triazine compound. Preferably, the polyphosphate contains two or more cations of 1,3,5-triazine compounds. The "at least one cation of a 1,3,5-triazine compound" in the polyphosphate is preferably the corresponding cation of one or more 1,3,5-triazine compounds obtained by protonation. Generally, these are the corresponding ammonium ions of one or more 1,3,5-triazine compounds mainly containing an amino group, such as melamine, melam, or melem.

[0012] According to the present invention, the flame retardant further comprises at least one melamine condensation product, i.e., one or more condensation products.

[0013] The term "condensation product" of melamine refers to a molecule formed by the condensation reaction of two or more melamine molecules, such as melam, melem, or melon. This term also encompasses the protonated forms of these compounds, i.e., the corresponding cations obtained by protonation.

[0014] In a preferred embodiment of the present invention, the flame retardant according to the present invention has a cationic form of a condensation product of melamine, and this cation is preferably the cation of the polyphosphate, that is, another 1,3,5-triazine compound of the at least one 1,3,5-triazine compound of the polyphosphate. Therefore, the polyphosphate contains at least a cation of melamine and a condensation product of melamine such as melem. In this case, the flame retardant may consist only of the polyphosphate. Such a polyphosphate can be obtained by adding a condensation product of melamine during adjustment.

[0015] In other embodiments, when the condensation product of melamine contained in the flame retardant is in the form of a cation bonded to the polyphosphate, the flame retardant may further contain other components.

[0016] However, the condensation product may be present in the flame retardant as an additional component to the polyphosphate, and as a result, the flame retardant becomes a composition containing both the polyphosphate and the condensation product of melamine, and optionally further components. In such a composition, the condensation product may be present in a non-ionic form of a salt other than the polyphosphate and / or as a cation.

[0017] Of course, the flame retardant may also be constituted by a combination of the above embodiments. That is, one kind of the cation of the polyphosphate is a protonated form of the condensation product of melamine, and the flame retardant contains at least one kind of the condensation product of melamine in a non-ionic form of another salt and / or as a cation as an additional component.

[0018] The polyphosphate of the flame retardant according to the present invention can be represented in a simplified manner by the following general formula.

[0019]

Chemical formula

[0020] Here, "T" x" represents at least one kind of 1,3,5-triazine compound, and "n" represents the average degree of condensation. The chain ends of the polyphosphate (formed by -H or -OH in the above structural formula) may be formed by the 1,3,5-triazine compound.

[0021] The inventors have confirmed that the combination of the polyphosphate according to the present invention containing at least one kind of cation of melamine and at least one kind of condensation product of melamine exhibits particularly remarkable flame retardant properties. Furthermore, the migration behavior of the polyphosphate is favorably affected by such a combination, that is, the degree to which the polyphosphate is washed away from the material to be protected, particularly the polymer material, is significantly reduced.

[0022] Although not limited to this theory, the inventors speculate that the condensation product of melamine crosslinks between individual macromolecules of the polyphosphate via hydrogen bonds, that is, a larger supramolecular aggregate is formed by intermolecular interactions, and it is more difficult for the aggregate to migrate out of the material. Therefore, when the flame retardant is incorporated into or coated on the matrix material to be protected, the condensation product acts as a kind of "supramolecular crosslinking agent" to strengthen the fixation of the flame retardant polyphosphate in or on the matrix material.

[0023] At least one kind of the condensation product of melamine further stabilizes the polyphosphate. For example, in a synergistic combination with an acidic flame retardant such as aluminum phosphinate described above, no acid-base exchange reaction occurs. Therefore, even at the high temperatures common in extrusion processing, these combinations can be used without decomposition of the polyphosphate.

[0024] On the other hand, in pure melamine polyphosphate, in the first step, the melamine cation can be replaced by a more acidic aluminum cation. Thereafter, if applicable, melamine may sublime and release phosphinic acid.

[0025] Furthermore, condensed melamine derivatives have significantly higher decomposition temperatures (over 600°C) and are more stable than melamine (which decomposes over 350°C) during plastic processing.

[0026] Therefore, the flame retardant according to the present invention guarantees unlimited processability of the plastic, even during high-temperature processing across multiple processing stages.

[0027] Flame-retardant plastics undergo numerous reshaping and processing steps within the value chain (such as extrusion and injection molding), but their physical properties remain virtually unchanged or change only slightly.

[0028] Furthermore, plastics containing the flame retardant according to the present invention eliminate the need for toxic and / or nearly non-biodegradable flame retardants, making them highly suitable for recycling aimed at a circular economy of plastics.

[0029] Particularly preferably, at least one of the melamine condensation products is included in the flame retardant as one of the cations of the polyphosphate, in other words, the melamine condensation product is one of the at least one 1,3,5-triazine compounds, and its cation is included in the polyphosphate.

[0030] Such polyphosphates can be represented by the following structural formula.

[0031] [ka]

[0032] Here, "T x1 " is melamine, "T x2 " is a condensation product of melamine such as melam. The chain ends of the polyphosphate (formed by -H or -OH in the above structural formula) may be formed by a 1,3,5-triazine compound. The assumed resonance structures of the protonated form of melam, i.e., assumed T x2 H + One type is shown below.

[0033] [ka]

[0034] The hypothetical resonance structure of the protonated form of Merem, i.e., the hypothetical T x2 H + One type is shown below.

[0035] [ka]

[0036] In embodiments where the melamine condensation product is a type of polyphosphate cation, the effects of the present invention are particularly pronounced. Although not limited to this theory, the inventors hypothesize that in this case, a bond to at least one of the polyphosphate polymers already exists, and that this bond makes it easier to form supramolecular aggregates of further polyphosphate polymers, thereby increasing stability during processing.

[0037] In a particularly preferred embodiment of the present invention, the flame retardant has a minimum amount of condensation product relative to the amount of melamine cations of the polyphosphate.

[0038] Let X be the amount of melamine cations contained in the flame retardant, and Y be the amount of melamine condensation products (for example, as polyphosphate cations) contained in the flame retardant. As a result, the sum of these two components is obtained from X + Y. The proportion of the amount of condensation products in this sum is preferably at least 0.1%, or in other words, Y / (X+Y) ≥ 0.001.

[0039] More preferably, the proportion of the amount of substance of Y is at least 1%, more preferably at least 2%, particularly preferably at least 3%, even more preferably at least 5%, and most preferably at least 10%.

[0040] Preferably, the proportion of the amount of substance of Y is at most 50%, more preferably at most 20%, particularly preferably at most 15%, even more preferably at most 12%, and most preferably at most 10%.

[0041] The proportion of the amount of substance of Y is preferably in the range of 0.1 to 20%, more preferably in the range of 1 to 15%, even more preferably in the range of 2 to 12%, and most preferably in the range of at most 5 to 10%.

[0042] The average degree of condensation n of the polyphosphate is preferably at least 10, more preferably at least 20, even more preferably at least 50, and most preferably at least 100. The higher the degree of condensation, the greater the aggregates formed by the polyphosphate and the condensation product, and the further the tendency of the polyphosphate to migrate away, thereby enhancing the effects of the present invention.

[0043] The average degree of condensation n of polyphosphates can be determined according to known methods, such as those using NMR spectroscopy (J.Am.Chem.Soc.78, 5715 (1956)).

[0044] The average degree of condensation can also be described as the average chain length of polyphosphates.

[0045] The condensation product of melamine is preferably selected from the group consisting of melam, melem, and melon. Melam is particularly suitable for bonding polymers of polyphosphate due to its linear structure, and is therefore particularly preferred.

[0046] A 10% by weight aqueous slurry of a flame retardant containing polyphosphate preferably has a pH value of 5 or higher at 25°C. The pH value of the 10% by weight aqueous slurry of the flame retardant according to the present invention is determined by stirring 25 g of the flame retardant and 225 g of pure water at 25°C in a container and measuring the pH value of the resulting aqueous suspension using conventional means such as a pH meter or indicator paper. Particularly preferably, the pH value is in the range of 5 to 10, more preferably in the range of 5 to 8, and most preferably in the range of 5 to 7.

[0047] The 10% by weight aqueous slurry of the flame retardant polyphosphate according to the present invention preferably has a pH value of 5 or higher at 25°C. Particularly preferably, the pH value is in the range of 5 to 10, more preferably in the range of 5 to 8, and most preferably in the range of 5 to 7.

[0048] By having the pH value of the flame retardant and / or polyphosphate within the above range, the interaction between the matrix material to be protected and the synergistic flame retardant contained in that material is kept as low as possible. As a result, the flame retardant can be used in a variety of different matrix materials, especially pH-sensitive matrix materials.

[0049] The flame retardant activity, particularly the stability of the flame retardant during processing, can be improved by controlling the molar ratio of the total amount of at least one 1,3,5-triazine compound and the condensation product to the amount of phosphorus in the polyphosphate. This ratio is also referred to as the M / P ratio in the relevant literature. The total amount of at least one 1,3,5-triazine compound and the melamine condensation product also takes into account the protonated form, for example, the protonated form of melamine bound to the polyphosphate.

[0050] The inventors have confirmed that particularly good flame retardant properties and excellent processability can be obtained in a protected polymer material when the M / P ratio is 1.3 or less, preferably 1.2 or less, and more preferably 1.1 or less.

[0051] The polyphosphate according to the present invention is not required to contain only one cation of a 1,3,5-triazine compound, but may also contain further cations, such as ammonium ions. However, in order to maximize the flame retardant effect, it is preferable that the majority of the cations are formed from cations of at least one 1,3,5-triazine compound.

[0052] In particularly preferred embodiments, the proportion of the amount of cations of at least one 1,3,5-triazine compound to the amount of cations of the polyphosphate is preferably 50% or more, more preferably 70% or more, even more preferably 70%, very preferably 80% or more, especially very preferably 90% or more, and most preferably 95% or more. In one embodiment, the polyphosphate contains only the cations of at least one 1,3,5-triazine compound.

[0053] The proportion of the melamine cation in the cation of at least one 1,3,5-triazine compound is preferably 50% or more, more preferably 70% or more, even more preferably 80% or more, and most preferably 90% or more.

[0054] Insofar as the polyphosphate contains cations of melamine condensation products, the ratio of the amount of these cations to the amount of the polyphosphate cations is preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, and most preferably 20% or more.

[0055] As already mentioned, the polyphosphate according to the present invention is characterized by particularly advantageous release behavior and high stability during processing. The flame retardant according to the present invention cannot be removed from the matrix material into which the flame retardant is incorporated, or is removed in very small amounts, even by solvents such as water. This effect is particularly pronounced when the flame retardant according to the present invention has extremely low water solubility. This is most important for plastic products, especially in outdoor areas and humid indoor applications.

[0056] The water solubility of the flame retardant according to the present invention is preferably less than 0.1 g / 100 mL, and more preferably 0.05 g / 100 mL or less. Here, the water solubility is determined by preparing a 10 wt% aqueous slurry of the flame retardant with water at 25°C and measuring how much of the flame retardant according to the present invention has dissolved in the water after 24 hours.

[0057] The water solubility of the polyphosphate flame retardant according to the present invention is preferably less than 0.1 g / 100 mL, and more preferably 0.05 g / 100 mL or less.

[0058] The flame retardant according to the present invention is characterized by its exceptionally high decomposition temperature. The decomposition temperature can be determined by thermogravimetric analysis (TGA).

[0059] In a preferred embodiment of the present invention, the decomposition temperature, i.e., the temperature at which a mass loss of 2% by weight of the dry flame retardant occurs at a heating rate of 10 K / min in DSC measurement, is higher than 300°C, particularly preferably higher than 320°C, and even more preferably higher than 350°C.

[0060] Preferably, the decomposition temperature of the polyphosphate of the flame retardant according to the present invention, i.e., the temperature at which a mass loss of 2% by weight of the dry flame retardant occurs at a heating rate of 10 K / min in DSC measurement, is higher than 300°C, particularly preferably higher than 320°C, and even more preferably higher than 350°C.

[0061] In preferred embodiments, the flame retardant contains at least one further flame retardant component, which is preferably selected from nitrogen bases, melamine derivatives, phosphates, pyrophosphates, polyphosphates, organic and inorganic phosphinates, organic and inorganic phosphonates, and the aforementioned derivatives, and is preferably selected from ammonium polyphosphate, melamine-coated and / or coated / crosslinked ammonium polyphosphate particles, melamine resins, melamine derivatives, silanes, siloxanes, silicones, or polystyrene, and similarly, melamine, melam, melem, melon, ammelin, ammerido, 2-ureidomelamine, acetoganamine, benzoguanamine, diaminephenyltriazine, melamine salts and additions. The flame retardant is selected from 1,3,5-triazine compounds including melamine cyanurate, melamine borate, melamine orthophosphate, melamine pyrophosphate, dimelamine pyrophosphate, aluminum diethylphosphinate, melamine polyphosphate, oligomers and polymers of 1,3,5-triazine compounds, and polyphosphates of 1,3,5-triazine compounds, as well as guanine, piperazine phosphate, piperazine polyphosphate, ethylenediamine phosphate, pentaerythritol, dipentaerythritol, borate, zinc borate, zinc phosphate, zinc pyrophosphate, 1,3,5-trihydroxyethyl isocyanurate, 1,3,5-triglycidyl isocyanurate, triallyl isocyanurate, and derivatives of the aforementioned compounds. In preferred embodiments, the flame retardant includes wax, silicone, siloxane, fat, or mineral oil to better disperse further flame retardant components.

[0062] The flame retardant according to the present invention may further contain polyphosphates, the polyphosphates preferably comprising at least one cation of a 1,3,5-triazine compound.

[0063] Furthermore, the flame retardant of the present invention may also contain inorganic pigments and fillers (such as TiO2, Al2O3, Ba2SO4, etc.). Particularly preferred are inorganic pigments used in laser welding, laser marking, or laser structuring. Examples include copper salts such as copper hydroxide phosphate and copper pyrophosphate, or similar agents.

[0064] Particularly preferred, the flame retardant according to the present invention comprises at least one compound selected from the group consisting of phosphinates, diphosphinates such as aluminum diethylphosphinate, zinc borate, and zinc phosphate.

[0065] In preferred embodiments, the ratio of polyphosphate to at least one further flame retardant component in the flame retardant is 1:18 to 1:4, more preferably 1:9 to 1:2, even more preferably 1:6 to 1:1.5, and particularly preferably 1:4 to 1:1.25.

[0066] Particularly preferably, the flame retardant according to the present invention is halogen-free. The term "halogen-free" herein means that the weight percentage of halogen in the weight of the flame retardant is 1% by weight or less, preferably 0.5% by weight or less, particularly preferably 0.2% by weight or less, and most preferably 0.1% by weight or less.

[0067] In a preferred embodiment of the present invention, the flame retardant polyphosphate is halogen-free, that is, its halogen content is 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.2% by weight or less, and most preferably 0.1% by weight or less.

[0068] The present invention also relates to a plastic composition containing a plastic matrix and a flame retardant according to the present invention. In the sense of the present invention, the term “matrix” includes any material, and in particular any plastic or any plastic mixture that can incorporate the flame retardant according to the present invention or can be applied as a coating with the flame retardant according to the present invention. The term “plastic” is understood to include a material comprising 50% by weight or more, preferably 70% by weight or more of polymer.

[0069] The term "polymer" refers to a molecule constructed from one or more identical or similar structural units, i.e., constituent repeating units (IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"), ADMcNaught, A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), SJ Chalk. ISBN 0-9678550-9-8). Such polymers have more than 10 repeating units, preferably more than 15. The molar mass is preferably at least 3,000 g / mol, more preferably at least 5,000 g / mol, even more preferably at least 7,000 g / mol, and most preferably at least 10,000 g / mol.

[0070] The plastics according to the present invention, preferably containing a halogen-free flame retardant, are very suitable for recycling after use, especially when they contain no halogens at all or only small amounts of halogens.

[0071] The flame retardant according to the present invention has been shown to be particularly advantageous for use in the manufacture of plastic compositions by extrusion. The flame retardant according to the present invention can be easily incorporated into different plastic matrices by these methods without significantly affecting their processing properties. When using the flame retardant according to the present invention, the thermal and mechanical properties of the processed plastic matrix are also hardly affected.

[0072] The plastic matrices on which the flame retardant can be used are preferably selected from filled and unfilled vinyl polymers, olefin copolymers, olefin-based thermoplastic elastomers, olefin-based crosslinked thermoplastic elastomers, polyurethanes, filled and unfilled polyesters and copolyesters, styrene block copolymers, filled and unfilled polyamides and copolyamides, copolycarbons, and poly(meth)acrylates. Use with polymethacrylate and polyacrylate is particularly preferred, and use with polymethyl methacrylate is most preferred. In this regard, it is particularly advantageous that transparent polymethacrylate or polyacrylate can be obtained by adding the flame retardant according to the present invention.

[0073] However, in principle, the flame retardants according to the present invention can be used in all plastic matrices. These flame retardants can be used in polyamides (PA), polyesters such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), polyolefins such as polypropylene (PP) and polyethylene (PE), polystyrene (PS), styrene block copolymers such as ABS, SBS, SEES, SEPS, SEEPS, and MBS, polyurethane (PU), especially rigid and flexible PU foam, poly(meth)acrylate, polycarbonate, polysulfone, polyetherketone, polyphenylene oxide, polyphenylene sulfide, epoxy resin, polyvinyl butyral (PVB), polyphenylene oxide, polyacetal, polyoxymethylene, polyvinyl acetal, polystyrene Suitable for styrene, acrylic butadiene styrene (ABS), acrylonitrile styrene acrylic ester (ASA), polycarbonate, polyhydroxyalkanoate (PHA), polybutylene succinate (PBS), polyethersulfone, polysulfonate, polytetrafluoroethylene (PTFE), polyurea, formaldehyde resin, melamine resin, polyether ketone, polyvinyl chloride, polylactic acid, silicone, polysiloxane, phenolic resin, poly(imide), bismaleimidotriazine, thermoplastic elastomers (TPEs), thermoplastic urethane elastomers (TPU-U), thermoplastic polyurethane, copolymers, rubber, and / or mixtures of the aforementioned polymers.

[0074] The flame retardant according to the present invention is particularly suitable for use in plastic matrices that are processed at high temperatures, such as polyamides or polyesters, and is especially preferred for use in PA6.6 or PA6, or in high-temperature polyamides such as polyamide 4.6, semi-aromatic polyamides, and polyamide 12. Because the flame retardant according to the present invention has high thermal stability, it can also be used in such plastics. It is especially preferred for use in glass fiber reinforced industrial plastics such as glass fiber reinforced PA6 and PA66, glass fiber reinforced mixtures thereof, and glass fiber reinforced PBT.

[0075] In preferred embodiments, the plastic matrix is ​​selected from filled, unfilled, and / or reinforced polyamides, polyesters, polyolefins, and polycarbonates. A filled plastic matrix is ​​understood to mean a plastic matrix containing one or more fillers, in particular metal hydroxides, which are in particular alkaline earth metal hydroxides, alkali metal hydroxides, and aluminum hydroxides; silicates, which are in particular nanocomposites, bentonite, phyllosilicates such as alkaline earth metal silicates and alkali metal silicates, and functionalized phyllosilicates; carbonates, which are in particular calcium carbonate; and selected from the group consisting of talc, clay, mica, silica, calcium sulfate, barium sulfate, aluminum hydroxide, magnesium hydroxide, glass fibers, glass particles and glass beads, wood flour, cellulose powder, soot, graphite, boehmite, and dyes.

[0076] All of the listed fillers may be in conventional forms and sizes known to those skilled in the art, or they may be in nanoscale forms, i.e., particles having an average diameter in the range of about 1 to about 200 nm, and can be used in plastic compositions.

[0077] To strengthen the plastic composition and enhance its mechanical stability, it is preferable to add glass fibers as a filler.

[0078] In a preferred embodiment, the flame retardant is introduced in an amount of 1 to 40% by weight, preferably 1 to 30% by weight, and particularly preferably 1 to 25% by weight, relative to the total weight of the plastic composition containing the flame retardant.

[0079] These ratios provide excellent flame retardancy while preventing significant changes in the properties of the plastic matrix, particularly its mechanical properties and thermal dimensional stability, both during processing and use.

[0080] Flame retardants can be introduced into matrix materials to be protected, particularly plastic matrix materials, in various ways. Firstly, flame retardants can be incorporated during the molding process. For example, when a plastic matrix material is extruded, the flame retardant can be supplied during the extrusion process, for example, as an easily incorporated powder blend, as granules, or by masterbatch. In the sense of the present invention, a masterbatch is a polymer material in the form of granules or powder, containing a flame retardant and optionally further additives, each at a higher concentration than the concentration in the final use. To prepare a plastic composition, a masterbatch or various masterbatches are combined with a plastic matrix material that does not contain the flame retardant contained in the masterbatch, in amounts or ratios such that the concentration of the flame retardant in the final product is desired. Compared to the addition of various substances in paste, powder, or liquid form, masterbatches have the advantage of ensuring a high level of processing safety and being very suitable for processing and incorporation. Through extrusion, the flame retardant is evenly dispersed within the plastic matrix.

[0081] The introduction of a composition into a polymer material can be confirmed by appropriate analytical techniques, particularly NMR spectroscopy or IR spectroscopy.

[0082] The present invention also relates to polyphosphates as defined in claims 1 to 10, preferably claims 2 to 10, and more particularly to polyphosphates comprising cations of at least two 1,3,5-triazine compounds, wherein one of the at least two 1,3,5-triazine compounds is melamine, and the other of the at least two 1,3,5-triazine compounds is a condensation product of melamine, preferably melam.

[0083] The present invention also relates to the flame retardant effect of polyphosphates preferably containing melamine cations, and / or the use of melamine condensation products to enhance stability and / or processability.

[0084] The present invention also relates to the use of a flame retardant according to the present invention for imparting flame retardancy to materials, particularly plastic materials, preferably thermoplastic materials.

[0085] The present invention also relates to the use of the flame retardant according to the present invention as a coating material, and more preferably as a coating material for wood, metal, or plastic matrix materials. In particular, its use is preferred for so-called natural fiber reinforced plastics, preferably wood-plastic composites, i.e., composite materials made of wood fibers and plastic. Coating is understood to mean a method in accordance with DIN 8580 of applying an adhesive layer of an intangible material to the surface of a workpiece. [Examples]

[0086] [Table 1]

[0087] Measurement method UL94 test For each measurement, five test specimens were mounted vertically to clamps, with their free ends held in the Bunsen burner flame. Fuel time and the fall of the burning portion were evaluated using cotton balls placed beneath each specimen. The experiment and flame contact with a 2cm high Bunsen burner flame were precisely performed according to the specifications of UL (Underwriter Laboratories) standard UL94.

[0088] As a result, fire safety classifications ranging from V-0 to V-2 can be obtained. In this regard, V-0 means that the total burning time of the five test specimens was less than 50 seconds, and the cotton ball did not ignite due to the dropping, annealing, or burning components of the specimens. Classification V-1 means that the total burning time of the five test specimens was greater than 50 seconds but less than 250 seconds, and the cotton ball did not ignite. V-2 means that the total burning time of the five test specimens was less than 250 seconds, and the cotton ball ignited in at least one of the five tests due to the dropping of components from the specimens. The abbreviation NC stands for "unclassifiable," and means that a total burning time exceeding 250 seconds was measured. In most cases of unclassifiable, the specimens burned completely.

[0089] thermogravimetric analysis Thermogravimetric analysis (TGA) was performed using a Simultaneous Thermogravimetry-Dynamic Differential Calorimetry (STA / TG-DSC) instrument (model STA409 PC / 3 / H Luxx, Netzsch Geratebau GmbH) under a nitrogen atmosphere at a heating rate of 10 K / min in the range of 30°C to 500°C. The initial weight of the sample was 12–15 mg. The TGA curve was evaluated using NETZSCH Proteus software.

[0090] pH value measurement, conductivity measurement The pH value was measured in accordance with European ISO 787-9. For this purpose, a 10% by weight suspension of the flame retardant according to the present invention was prepared by stirring in distilled water (at 25°C). In each case, two equivalent batches were prepared, but the difference in measured pH values ​​never exceeded 0.3 units. A pH / conductivity combined sensor (Mettler Toledo, SevenMulti S470 Excellence) was used for measurement, allowing the conductivity of the suspension to be measured simultaneously with the pH value.

[0091] Measurement of the bound 1,3,5-triazine compound The ionic forms of each 1,3,5-triazine compound bound to polyphosphates, i.e., the content of melamine and its congeners, were measured using HPLC-UV. Therefore, first, the free portion of the corresponding compound in the sample was measured, and then the whole portion after hydrolysis with concentrated phosphoric acid was measured. The content of the bound 1,3,5-triazine compound was determined from the difference. To perform hydrolysis, 20-30 mg (±0.1 mg) of the sample was placed on a chemical balance in a 100 ml beaker, filled with 85% phosphoric acid up to 50.00 g, and held at 100°C for 30 minutes. The substance was identified in the UV range at a wavelength of 230 nm by measuring the HPLC retention time in two different column phases: "reverse phase" and "strong cation exchanger" (see table below).

[0092] [Table 2]

[0093] Evaluation of processability and flame retardancy results Processability was measured by incorporating the conventional processing agent into PA6 during extrusion using a twin-screw extruder. Granules with a particle size of approximately 3 × 1 × 1 mm were produced under normal extrusion conditions for PA6 using a Thermo Fisher Scientific Model Process 11 twin-screw extruder. The extrusion process was performed at a rate of approximately 5 kg / hour, a screw speed of 300 rpm, and an extrusion zone temperature of approximately 280°C. Processability, including potential non-uniformity and bubble formation, was evaluated by microscopic examination. Subsequent hot pressing yielded multiple UL94-compliant test specimens with the flame retardant properties shown in the table below. The weight ratio of the synergistic flame retardant mixture of aluminum diethylphosphinate exolite OP1230 and the flame retardant according to the present invention (weight ratio 2:1) was 19% each.

[0094] Determination of M / P ratio The total phosphorus and nitrogen content for calculating the M / P ratio was measured as described below. Total phosphorus content was measured by photometric P2O5 measurement. For this purpose, the sample was hydrolyzed for a total of 30 minutes at a maximum power of 1,000 watts using a closed acid digestion system (65% nitric acid). Photometric measurements were performed at 430 nm relative to the reagent blank value. Nitrogen was measured by titration. For this purpose, nitrogen bound as ammonium in the sample was separated from the sample by disrupting the organic matrix. Oxidative acid digestion was carried out using concentrated sulfuric acid while boiling in a closed digestion apparatus (heating bank including Turbosog). In this process, organic matter is oxidatively destroyed, and SO2 produced by the reduction of concentrated sulfuric acid is removed. Upon addition of an alkaline solution, nitrogen is converted to its volatile form as water vapor, selectively removed by distillation, and its volume is measured. The amount released is measured by titration with H2SO4.

[0095] Preparation example Example I of the present invention A 100-liter reactor equipped with a stirrer was filled with 50 liters of pure water. To this water, 19.9 kg of orthophosphoric acid (85% by weight H3PO4) was added while stirring at room temperature. Next, 20 kg of melamine and 7.18 kg of melam were slowly added at 50°C while constantly stirring. After the addition, the excess water was evaporated by increasing the temperature until the residual water content in the mixture was 0.1% by weight or less. The resulting phosphate was then heated to 310°C to initiate a reaction that formed a polyphosphate.

[0096] Example II of the present invention A 100-liter reactor equipped with a stirrer was filled with 50 liters of pure water. To this water, 16.2 kg of orthophosphoric acid (85% by weight H3PO4) was added while stirring at room temperature. Next, 20 kg of melamine and 1.37 kg of melam were slowly added at 50°C while constantly stirring. After the addition, the excess water was evaporated by increasing the temperature until the residual water content in the mixture was 0.1% by weight or less. The resulting phosphate was then heated to 310°C to initiate a reaction that formed a polyphosphate.

[0097] Comparative Example A 100-liter reactor equipped with a stirrer was filled with 50 liters of pure water. To this water, 17.4 kg of orthophosphoric acid (85% by weight H3PO4) was added while stirring at room temperature. Next, 20 kg of melamine was slowly added at 50°C while constantly stirring. After the addition, the excess water was evaporated by increasing the temperature until the residual water content in the mixture was 0.1% by weight or less. The resulting phosphate was then heated to 310°C to initiate a reaction that formed a polyphosphate.

[0098] The resulting flame retardant has the following material properties.

[0099] [Table 3]

Claims

1. A flame retardant containing polyphosphate, The polyphosphate is a flame retardant having a cation of at least one 1,3,5-triazine compound, One of the at least one 1,3,5-triazine compounds is melamine, and the proportion of the melamine cation in the cation of the at least one 1,3,5-triazine compound is 50% or more. The flame retardant comprises at least one melamine condensation product, A flame retardant characterized in that, when X is the amount of melamine cations in the flame retardant and Y is the amount of at least one of the melamine condensation products, the proportion of Y in the total amount of X + Y is 1% or more, or 2% or more and 20% or less.

2. The flame retardant according to claim 1, characterized in that at least one of the melamine condensation products is one of the at least one 1,3,5-triazine compounds, and its cation is contained in the polyphosphate.

3. The flame retardant according to claim 1 or 2, characterized in that the average degree of condensation n of the polyphosphate is 10 to 500 or 20 to 250.

4. The flame retardant according to claim 1 or 2, characterized in that at least one of the melamine condensation products is selected from the group consisting of melam, melem, and melon.

5. The flame retardant according to claim 1 or 2, characterized in that the pH value of a 10% by weight slurry of the flame retardant and / or the polyphosphate in water at 25°C is 5 or higher.

6. The flame retardant according to claim 1 or 2, characterized in that the amount of substance ratio of the amount of at least one 1,3,5-triazine compound to phosphorus and the sum of the amount of at least one melamine condensation product is 1.3 or less or 1.1 or less.

7. The flame retardant according to claim 1 or 2, characterized in that the cation of at least one 1,3,5-triazine compound accounts for 90% or more of the total proportion of cations in the polyphosphate.

8. The flame retardant according to claim 1 or 2, characterized in that the water solubility of the flame retardant and / or the polyphosphate is 0.1 g / 100 mL or less or 0.07 g / 100 mL or less.

9. The flame retardant according to claim 1 or 2, characterized in that the decomposition temperature of the flame retardant and / or the polyphosphate is higher than 320°C.

10. The flame retardant according to claim 9, characterized in that it includes, as an additional component, at least one component selected from the group consisting of phosphinate, diphosphinate, or aluminum diethylphosphinate, zinc borate, and zinc phosphate.

11. A plastic composition comprising a plastic matrix and a flame retardant as defined in claim 1 or 2.

12. A polyphosphate as defined in claim 1 or 2.